In second position, an ad from Save the Children created by Don't Panic was shared 788,843 times.

The ad, which has been widely well-received online, features a British schoolgirl going about her daily routine in second-long sequences as the country is plunged into war, to raise awareness of the Syrian crisis.

Meanwhile, a call to ban the word "bossy" to inspire female leaders of the future, starring Facebook's chief operating officer, Cheryl Sandberg, the former US Secretary of State Condoleezza Rice and the pop star Beyonce, has been shared just over 64,000 times.

The film, which features shots of famous and inspiring women talking about the negative reactions from some to their rise to fame and power, was created by BBDO New York and took fifth place this week.

Samsung is the only brand to feature four times in this week's chart. Official introductions to its latest Galaxy S5 smartphone and Gear 2 smart watches, created in-house, have been shared a combined 439,446 times this week.

The chart is collated by Unruly and ranks ads on YouTube by the number of shares across Facebook, Twitter and the blogosphere. Ads older than 30 days are not included.

1. Wren Clothing "first kiss" by Tatia Plleva

952,802 shares this week | 952,802 shares all-time

2. Save the Children "most shocking second a day video" by Don't Panic London